This invention is an improvement over U.S. Pat. No. 7,308,968 (the '968 patent) for a transportable rescue conveyer in that it provides unique powered aerial ladder mechanism that extends the stiles of the ladder to reach a building, ship or oil-drilling platform and also moves the rungs to raise and lower the fireman, a person rescued, and any load the fireman may need to raise or lower with him. Unlike the '968 patent, this improvement provides a powered carriage for a fire and rescue truck that eliminates a significant amount of weight due to the absence of powered rungs and the rung storage needed for operability. Less weight means that two parallel pairs of booms can be used to enable two powered carriages to independently move up and down the booms.
A telescopic lift is taught in U.S. Pat. No. 3,891,062 B1 (the '062 patent), which is used for construction works. It is a mobile lift made up of a rectilinear guide adjustably held in upward inclined position by a support having a base of which the end is wheel-mounted so that the lift may be displaced. A load carrier is movably mounted on a guide and a cable, of which one end is secured on the carrier and the other winds around a mechanical winch after having wound around a pulley, allows displacement of the carrier on the guide.
The present invention is distinctive over the '062 patent in using two cables one mounted to the top end of the carriage and one mounted to the bottom end. The dual cables add safety in the event a single cable breaks and enables powered transit of the carriage in both directions while the booms are being extended or contracted. This feature is enabled by the provision of dual winches that are computer controlled to rotate in any direction as required to accommodate carriage movement while extending or contracting the extensible booms. The present invention is further distinctive with the inclusion of a tilting boom at the elevated end of the booms. The tilting boom enables the carriage to adjust to horizontal for loading, unloading and working at height. The tilting boom also permits adjustment so that the boom can lean on a wall.